1. While it is a serious problem, I highly doubt it's extinction level serious.

2. It seems fairly specific to our technological path, I doubt that any advanced civilization is bound to produce micro plastics.

3. Ecological problems in general might be a better candidate at least as a part of the solution.

@ProjectVictory Thank you for the feedback. I'm curious about point #2. Plastics are so incredibly useful as containers, conduits, adhesives, etc., that I'm trying to imagine a civilization that wouldn't try using them. Even a planet of sentient trees, I think, would find them useful. Are you imagining maybe different environmental temperatures and chemistries? Not arguing, just curious.

@Slackhammer The biology and chemistry of alien life might be different enough that

A. Micropastics don't cause them harm.

B. They are difficult to produce from available resources / useless at temperatures that alien life prefers.

C. There are other even more useful materials that they use instead.

Alien life might not be based on carbon and water at all so alien technology might use types of chemistry that we have no idea about. It's all very speculative, obviously.

I think microplastics might actually be what gets us past the great filter.

How so?

If they can get into our testicles, they can do anything